Diagnosing non-melanoma skin cancer

Diagnosis is the process of finding the cause of a health problem. The process of diagnosis may seem long and frustrating, but it is important for the doctor to rule out other reasons for a health problem before making a cancer diagnosis. Diagnostic tests for non-melanoma skin cancer are usually done when:

the symptoms of non-melanoma skin cancer are present, such as a sore that does not heal or a changing spot or growth

the doctor suspects non-melanoma skin cancer after talking with a person about their health and completing a physical examination

Basal cell carcinoma (BCC) rarely spreads, so tests to determine the stage (how far the cancer has progressed) are not usually done. Squamous cell carcinoma (SCC) is more likely to spread, though the risk is relatively small.

Many of the same tests used to initially diagnose cancer are used to determine the stage. Your doctor may also order other tests to check your general health and to help plan your treatment. Tests may include the following.

The medical history is a record of present symptoms, risk factors and all the medical events and problems a person has had in the past. The medical history of a person’s family may also help the doctor to diagnose non-melanoma skin cancer.

A skin examination allows the doctor to look for any signs of non-melanoma skin cancer. During the examination, the doctor may:

note the size, shape, colour and surface texture of the growth or spot

ask about bleeding or scaling

ask how long the spot has been present

check the lymph nodes near the area (if the doctor suspects squamous cell carcinoma)

examine the whole body, especially areas that are frequently exposed to the sun

Dermoscopy

In addition to the physical skin examination, the doctor may also use dermoscopy, also known as surface microscopy or epiluminescence microscopy. Dermoscopy is used to examine pigmented or non-pigmented lesions (abnormal areas) for changes that are not visible to the naked eye.

Before the exam, the lesion may be covered with mineral oil to cut down on some of the light reflection from the skin. This makes the lesion easier to see.

Aura device

Health Canada has recently approved the Verisante Aura, which is a device that visually scans a mole or lesion to determine if it is cancerous. The Aura device is non-invasive. It uses Raman spectroscopy to analyze chemical reactions in the skin, providing immediate and accurate results. It can be used by healthcare professionals to detect both melanoma and non-melanoma skin cancers. It may not be available at all centres.

During a biopsy, tissues or cells are removed from the body so they can be tested in a laboratory. The pathology report from the laboratory will confirm whether or not cancer cells are present in the sample.

Different methods can be used for a skin biopsy. The type of biopsy done depends on the type of skin cancer and the location and size of the affected area. The biopsies that could be used for non-melanoma skin cancer are:

Excisional biopsy is used when the tumour involves deeper layers of the skin and the entire tumour can be removed. If the entire tumour is removed during biopsy, the person may not need any further treatment.

Incisional biopsy is used when the tumour involves deeper layers of the skin and the entire tumour cannot be removed.

A CT scan uses special x-ray equipment to make 3-dimensional and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures. It is used to see if the cancer has spread to the lymph nodes or other internal organs.

MRI uses powerful magnetic forces and radio-frequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-dimensional pictures. It is used to see if cancer has spread to the lymph nodes or other internal organs.

When the lymph nodes are large and firm to the touch, the doctor may do a lymph node biopsy to find out if the cancer has spread to the nearby lymph nodes. The types of biopsies that could be used are: